1. Field of the Invention
This invention relates to brackets for concrete forms.
2. The Prior Art
Structures of various types require a suitable foundation thereunder in order to prevent subsidence, frost upheaval, and other disturbances of the integrity of the wall structure. Construction of the building foundation is initiated by fabricating a footing in an excavation with the footing following the outline of the proposed load bearing wall structure. Footings are fabricated from concrete with the specific dimensions, height and width, dictated according to the structure to be erected thereupon as directed by the local building ordinance requirements. The top surface of the footing is prepared to establish the grade of the footing.
Conventionally, the concrete footing structure is erected by preparing an outline of the footing with form walls which define the size of the footing structure. The footing form walls are prepared so as to achieve the appropriate width and height of the footing in addition to establishing the appropriate grade for the footing. The grade is initially established with the top edge of the form walls and the footing form is thereafter filled with concrete flush with the top edge of the form walls so that the concrete surface corresponds to the grade as set by the top edge of the form walls.
To establish these various dimensions of the footing form, it has been conventional to use wooden stakes and wooden cross ties in combination with wooden form walls. The footing form walls are usually lengths of standard 2.times. 10 or 2.times. 12 inch lumber which has been sprayed with a form release agent. Wooden 1.times. 2 inch cross ties are nailed to the form walls to provide lateral support while the wooden stakes are driven into the ground to support the form walls against the outward displacement by the hydraulic pressure of the fresh concrete. Where necessary, the stakes are also nailed to the form walls to support the form walls above the ground surface in order to establish the grade of the footing form.
Fluid concrete exerts substantial hydraulic pressure against the form walls which, unless they are adequately braced, will be forced outwardly resulting in slumping, wasted concrete, and loss of footing integrity, particularly with respect to the grade of the footing. To overcome this problem it is conventional to drive additional support stakes into the ground as insurance against the concrete forcing the form walls outwardly.
However, in rocky or hard ground it is extremely difficult to drive wooden stakes into the ground without their splitting and/or otherwise being damaged. Conversely, stakes are readily driven in sandy soil but sandy soil generally does not hold the stakes against the pressure of the concrete with the same undesirable results as set forth hereinbefore.
Furthermore, the foregoing described conventional technique of preparing footings consumes considerable quantities of man-hours with respect to obtaining (a) the correct dimensions of the footing, (b) the proper grade of the footing, and (c) removing the stakes, cross ties and side form walls from the footing when the concrete is set sufficiently. Furthermore, an excessive number of stakes and cross ties are destroyed after only a single use. Additionally, since the concrete is poured and finished flush with the top edges of the form walls, the cross ties nailed to the top edges of the form walls hinder the finishing of the top surface of the concrete adjacent the cross ties.
Numerous devices have been disclosed which are used to maintain the vertical integrity of concrete form walls. These generally include some form of tie arrangement wherein one form wall is physically connected to the corresponding form wall through a tie member. The concrete is poured between the form walls and thereby completely surrounds and embeds the tie member. After the concrete has sufficiently set the ends of the ties are cut leaving the main body of the tie embedded in the concrete while the form walls are removed from the concrete wall. Numerous examples of these types of concrete form ties may be found, for example, in U.S. Pat. Nos. 645,325; 972,036; 1,550,000; 1,712,631; 1,746,298; 1,769,292; and 2,020,515. In each of the foregoing patents, the form tie is specifically designed to remain embedded within the concrete structure. Even in those cases where the form tie would be used on the top surface of the concrete, the tie would still be either flush with or partially embedded in the concrete surface. As such, it is difficult to suitably finish the concrete surface immediately adjacent the tie.
In view of the foregoing it would be a significant advancement in the art to provide a concrete form bracket which securely engages the side form walls to securely hold them in a vertical position and restrain them against the hydraulic pressure of the concrete poured therein. The bracket should also include means for readily accommmodating establishment of the proper width and grade for the form walls and provide means for allowing working of the concrete underneath the crosspiece of the bracket. Such an invention is disclosed herein.